Does Toyota's variable valve timing cause horsepower and/or torque to peak at higher RPM than it would without VVT?
- posted
18 years ago
Does Toyota's variable valve timing cause horsepower and/or torque to peak at higher RPM than it would without VVT?
BMW uses Variable Valve Timing they call VANOS.
I am pretty sure that the VANOS does not give torque and horsepower at speed, but rather alters valve timing to give more torque on the lower end of the power band. VANOS works off the line, then goes away to let the engine do its own thing above speeds of about 3000 rpm.
I don't think it affects the peaks, it affects the low end of the curve.
I believe the purpose of Toyota's VVT is to get more horsepower and/or torque at a given RPM than to change where the peak HP and torque come in. I wouldn't think that the RPM at which these occur is any different.
It can be tailored for different applications. The 1.8 litre corolla three door hatch engine in the UK has 192hp at 7800rpm and 180Nm torque at an incredibly high 6800rpm.
On the other hand the corolla verso 1.8 has 130hp at 6000rpm and 170Nm at
4200rpm.Both are VVTI engines
Huw
That engine is the 2ZZ-GE and has 189bhp. And it's VVTL-i (notice the L for Lift)
Most probably the 1ZZ-FE as also found in the 'slower' Celica.
One is VVT-i, the other is VVTL-i
Hmm, yes. After looking more closely they even have different cylinder dimensions.
Huw
Well you're right by that it can be tailored for different applications. A better comparision would be the Corolla Verso 1.8 you mention which puts out a max of 130bhp at 6000rpm, yet the same engine in the 'slow' Celica puts out a max of 140bhp at 6400rpm.
They lack that nice low-down torque that makes town driving pleasant and you have to rev the crackers off them to get any decent power.
Actually I had a 'slow' Celica (140bhp 1ZZ-FE), and the one thing I loved about it was that you could put your foot down at as little as 1500rpm and it'd go. I've now got a mk2 MR2 (168bhp 3S-GE), and there is just no power below
3000rpm :(
I was in the 190hp a few months back and it was like a bag of jello with an elastic throttle. I have a 5th gen Alltrac, low compression
3S-GTE, obviously with turbo. Based on the same engine as yours but with a turbo attached. I've got plenty more torque than the 190 i was in below 3K and absolute gobfulls more when the turbo spools. IIRC though the peak torque for the 3SGTE is at 3200rpm (225-250lb ft) Your 3SGE should surely have more torque than mine when mines off-boost (below 2300rpm approx) as you have higher compression? Maybe yours has a problem?Yota Engines: Figures are Power then Torque
3S-GE DOHC 4/50 86- 150@6400 133@4800 3S-GE DOHC 4/50 90- 156@6600 137@4800 3S-GE DOHC 4/50 94 175@7000 137@4800 3S-GE DOHC+VVT-i 98- 190@7000 152@6000 3S-GE DOHC+VVT-i 98- 200@7000 152@6000 3S-GE DOHC+DualVVT-i 99 200@7000 159@4800 3S-GE DOHC+DualVVT-i 99 210@7600 159@6400 3S-GTE DOHC 4/50 90- 200@6000 200@3200 max 11.0psi/0.75 bar 3S-GTE DOHC 4/50 90-93 225@6000 225@3200Torque curve for a celica ST205 3SGTE (same as Mk3 MR2 turbo) shows at
2000rpm (off boost completely) is has 130ftlb which isnt far off the max of your mr2 and still close to the vvti engines, yet nowhere near the rpm levels. Without seeing the actual curves its hard to tell what the values are below the max :( J
I did ask around about this shortly after getting it, but apparently it's normal.
Stick a turbo conversion in ;)
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